What Is Histamine? (2024)

Histamine is a chemical throughout your body that plays a role in allergies and several conditions. Histamine triggers include allergens and certain foods. However, there are ways to reduce histamine.

Histamine is a substance your cells produce to help your immune system respond to allergy triggers.

Histamine is an important part of your allergic response. That’s why people use antihistamines to treat allergy symptoms caused by having too much histamine in their bodies.

But histamine is also involved in various bodily functions that can affect your gastrointestinal (GI) tract, brain, and overall immune response.

Read on to learn more about how histamine works, what can trigger a histamine response, and how to seek treatment for conditions that might cause an overload of histamine in your body.

Histamine is an amine involved in immune responses all over your body. Amines are made of nitrogen atoms bonded with other atoms — in this case, with hydrogen — and can bond to many other cells throughout the body to help cells respond to injury or exposure to allergy triggers.

You have histamine everywhere inside you, but its highest concentrations are in your:

• lungs, where it helps resist foreign substances like allergens
• basophils, a type of white blood cell involved in inflammatory responses
• mast cells, a type of immune cell found in your connective tissues also involved in inflammation

Your immune system releases immune cells in response to inflammatory triggers like injuries or allergic substances. Histamine is an important mediator in this process.

Some of the most well-known immune responses that involve histamine include:

• nociception: a pain response triggered when your body believes it’s being harmed
• vasodilation: the widening of your blood vessels to increase blood flow into an area
• bronchoconstriction: a tightening of muscles in your airways to restrict the flow of air in and out of your lungs
• gastric acid secretion: an increase of stomach acid production to help your stomach maintain its typical acidity
• airway mucus production: an increase in mucus in your airways to help capture allergens
• vascular permeability: a change in blood vessel walls to allow cells to pass through them more easily

Common symptoms of high histamine levels include:

• GI symptoms like abdominal pain, bloating, or diarrhea
• skin symptoms like itchiness or hives
• migraine
• sinus drainage and nasal congestion
• fatigue
• dizziness
• itchy skin
• changes to your menstrual cycle
• high blood pressure
• changes in your heart rate
• anxiety

Some common triggers of histamine include:

• air pollution
• dust
• eating large meals
• airborne chemicals, especially artificial fragrances
• dehydration

Foods that trigger histamine

Foods that can trigger histamine include:

• pork
• beans
• chocolate
• bananas
• tomatoes
• legumes, such as peanuts
• alcohol
• citrus
• nuts, specifically walnuts and cashews
• food dyes
• natural flavors in some foods

Some foods that trigger histamine responses are called histamine liberators. This means that they have high levels of substances called biogenic amines. Histamine is one of several biogenic amines.

Some histamine liberators that trigger histamine include:

• canned food
• wine
• pickled vegetables
• fermented drinks
• highly fermented cheeses
• fish
• seafood

Histamine intolerance happens when your body can’t properly break down histamine.

This can happen when you don’t have enough of an enzyme called diamine oxidase (DAO), which breaks down histamine. Without enough DAO, histamine can build up to high levels and affect many bodily functions.

Common causes of histamine intolerance include:

• gene mutations that cause DAO deficiency
• medications for blood pressure or depression that affect how DAO is produced
• GI conditions that can cause DAO deficiency, such as IBD
• a diet high in histamine-rich foods or foods that affect how DAO is produced
• histamine buildup from an overgrowth of bacteria that produce histamine

You have many options for clearing histamine from your body depending on what parts of your body are involved, including:

• H1 antihistamines: These help treat allergy symptoms due to triggers like dust or pollen.
• H2 antihistamines: These help reduce stomach acid production involved in GI tract symptoms.
• Corticosteroids: Corticosteroids help reduce inflammation involved in symptoms affecting your skin or respiratory tract.
• Epinephrine: This hormone stops your airways from closing up (anaphylaxis) when you have a severe immune response.
• Supplements: Supplementation with vitamin B6 or vitamin C may help balance out histamine levels in your body.

Here are some of the most frequently asked questions about histamine.

What is a histamine dump?

A histamine dump happens when your body produces too much histamine that builds up in the brain. Histamine dumps often happen late at night or early in the morning. You might suddenly feel changes in body temperature, itchiness, or blood pressure changes as your histamine levels rise.

How do antihistamines work?

Antihistamines help stop histamine from binding to cells throughout your body that might produce too much inflammation.

Over-the-counter antihistamines like diphenhydramine (Benadryl) and cetirizine (Zyrtec) are common treatments for chronic allergies or asthma that result from an exaggerated immune response involving histamine.

You can also use antihistamines like ketotifen as mast cell stabilizers to treat conditions that involve the interaction of histamine with mast cells, such as MCAS.

Can drinking water flush out histamine?

There’s no clear link between drinking water and flushing out histamine when it builds up to high levels. But research suggests that dehydration can trigger immune responses that involve histamine.

Drinking enough water throughout the day may help reduce the chance of histamine-related responses across your body, including GI and asthma symptoms.

Histamine is known for its role in allergies and asthma. But it’s also involved in many other complex processes throughout your body. Histamine responses can also cause conditions that affect your GI tract and your nervous system responses.

Contact a doctor if you’re concerned that histamine may be playing a role in any disruptive symptoms you’re experiencing. Many treatments can help manage conditions like histamine intolerance and MCAS.